Optical projection apparatus



W. R. MENGEL.

` OPTICAL PROJECTION APPARATUS. APPLICATION HLED nc.2o,192o. nENEwEDyMAY 19,4922.

Patented Oct. 31, 1922.t

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/f'cyiam Jy @ZM/MK Patented oct. 31, 1922.

UNITED sTATEs PAT/ENT oFFlcE.

WILLIAM B. MENGEL, 0F CHICAGO, ILLINOIS, ASSIGNOR TO CHRISTEN J.PETERSON 0F OAK PARK, ILLINOISi` GPTICAL -PROJECTION' APPARATUS.`

Application filed December 20, 1920, Serial No. 431,855. Renewed May 19,1922. Serial No. 562,268.

To all whom, it may concern:

Be it known that I, WILLIAM R. MENcEL, a citizen of the United States ofAmerica,

and a resident of Chicago, in the county of' ing the subject matter ofmy prior Letters Patent No. 1,342,561, dated June 8, 1920, and has forits object- To provide `a structural formation and combination of partsin stereopticons and like optical projecting apparatus, adapted tointercept and dissipate the heat rays in the light path in a simple andeffective manner, with a view to provide against undue heating andignition of the inflammable picture film now generally used in such typeof apparatus, all as will hereinafter more fully appear,

In the accompanying drawing* Fig. 1, is a vertical vsection on line 1v1Fig. 2, of the film and objective carrying frame of an opticalprojection apparatus, having the present invention applied.

Fig. 2, is a horizontal section on line 2-2 Fig. 1.

Like reference numerals indicate like parts in bothl views.

Referring to the drawing 1, designates the vertical rear wall of thesupporting frame or housing for the fiim mechanism and the objective ofan opticall projection apparatus of the construction shown in my priorPatent No. 1,342,561, formed with a vertical channel 2 for the guidanceof the picture film and with the usual light passage 3 intermediate thewidth of said channel and interectmg n the j thelight pa'thof theapparatus. a present construction the light passagey 3 1s provided witha marginal flange or rim 4 adapted to receive a sheet orpanel 5 of glassor like transparent material, held in place in a detachable manner by aconfining frame 6 asvshown, to provide a bearing surface for theportion'of the picturefilm in the light path of the apparatus.

7 designates the film confining gate of the structure, arranged to swing.horizontally on a vertical side pivot 8 and provlded at its free endwith a fastening screw 9 and interposed spring 10, by which the gate issecured to the vertical wall 1 in a resilient manner. The gate 7 isformed with a vertical channely adapted to register with the aforesaidchannel 2 to aid in the guidance of the picture film, and with a lightpassage in line with the light passage 3 and with the light path of theapparatus. In the present construction said light passage of the gate 7is provided with a marginal rim or flange 11 adapted to receive a sheetor panel 12 of glass or like transparent material heldin place by aconfining frame 13 as shown so as to provide a bearing surface for theportion of the picture film in the light path of the apparatus.

14 designates a plate memberof a similarA detail construction to a likeplate number in my aforesaid Patent No. 1,342,561, and. secured to therear face of the film gate 7 by distance studs 15 toafford an open spacebetween the parts and provide a Ventilating passage for the air to aidin carrying away the heat which is communicated to the parts in actualuse. The plate member 14 is formed with a iight passage arranged in thelight path of the apparatus and is provided with a marginal rim` orflange 16 adapted to receive asheet orpanel 17-of glass or liketransparent material as shown.

With the present construction the panels or sheets 5, 12, and 17 lact ina very effective vmanner to intercept heat rays passing along the lightpath of the apparatus, and conduct the same to the metallic holdingparts from which the heat is carried away by the usual Ventilatingprovisions of the enclosing casing of the apparatus.

Having Athus fully described niy'said in- 9 vention whatv I claim as newand desire to tvveen said Wall, gate and transparent sheets for thedissipation of the intercepted heat rays.

2. In an optical projection apparatus of the type described, thecombination of a g housing Wall formed With a guide channel sage havingmarginal flanges, a sheet of transparent 'material tted in said marginalanges, a plate member secured in spaced relation to the rear `face ofthe lm gate to 15 provide a Ventilating duct between the parts, saidplate member Vhaving a light passage provided With marginal flanges, anda sheet of transparent material fitted in said iang'es. i

Illinois, this 15th day 20 Signedat Chicago, of December, 1920.

WILLIAM R. MENGEL.

